Fire brick



March 15,1927' NYGAARD FIRE BRICK Filed May 18,l 1925 l oooooooo oooololmloo oooooooo oooooo oooooooo oooooooo oooooooo oooooooo oooooooo Ill oooooooo ccoooooo ocoooooo ooxwloloooo 00000000 rl Patented Mar. 15, 1927.

UNITED STATES PATENT OFFICE.

OSCAR NYGAARD, F SAUGUS, MASSACHUSETTS, ASSIGNOR T0 BEBNITZ FURNACE .APPLIANCE COMIVANY, 0F BOSTON, MASSACHUSETTS, A CORPORATION 0F MASSA- CHUSETTS.

FIRE BRICK.

appiic'ation yiiieu may is, 1925. serial No. 31,227.

This invention relates to fire brick and is especially concerned with brick designed to be used in the walls of furnaces which are subject to sustained operation at high temperatures. For example, in furnaces for water tube boilers when the fuelis supplied by underfeed stokers and forced draft is applied, the heat in the fuel bed becomes so 'intense that the slag, clinkers and ash fuse to the furnace lining, andv when this fused mass is removed a part ofthe lining is chipped off Ywith it. The action then repeats, with the result that the life of the ining is greatly reduced. It has been found that this diiiiculty can be obviated by admitting air into the fuel bed along the portion of the furnace wall where the clinker formation occurs, the air serving t cool the wall face below the fusing point.

Also in modern boiler installations where 'pulverized fuel is used resulting in sustained operation at high temperatures it has been found advisable to uti ize air passages through the furnace walls for .the

purpose of cooling the walls and prolonging their life.

The present invention is especially concerned with the construction of furnace wallsf'where air "passages are desirable and it is the chief object of the invention to devise a brick which will be particularl ada ted for the requirements of such a wal Tlie nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

Referring now to the drawings,

40 Fi re 1 is a vertical cross sectional view of a rick embodying the present invention;

Fig. 2 is a front elevation of the rear vsection of the brick shown in Fig. 1;

Fig. 3 is a rear elevation of the front section of said brick;

Fig. 4 is a cross sectional view through a portion of a furnace showi a typical ventilated wall construction `wit a. lining' made vof brick of thelcliaracter shown in Fi 1;

5 Fig. 5 is a front view of a'portion o the wall shown in Fig. 4.

The brick shown comprises a front or facing section 2 and a rear or backing section 3. The front section is recessed, as

shown .at 4, to receive a central projection 5 extending forwardly from the front of the rear section 3, and the front Section also is provided with an internal shoulder .6 to limittlie distance that the projection 5 can be forced into the recess 4. When these sections have been assembled in the relationship shown in Fig. 1 and secured together by a layer of cement 7 the two parts are united both adhesively and also through the mechanical interlocking of the sections.

The shoulder 6 not only limits the -m0vement of the projection 5 into the recess 4, but it also spaces the end of this projection from the inner surface of the front section 2, and thus provides an air space or chamber 8 of substantial thickness and area between the central portions of the two sections. 'In other words, the marginal portions only of the two sections are united and the central areas of thesel parts are separated by the air space 8l Preferably several air holes or passages 10 are formed throu h the front section 2 and corresponding oles 12,` in alinement with the holes 10, are provided in 'the rear section 3. These holes preferably are tapered to allow for the ex ansion of the air as .it approaches thehig lly heated surface of the lining. Anotheriliole 13 is formed centrally through the rear section and opens into the air space 8 1n an offset relationship `to the holes- 10. I It is contemplated that the front section 2 will ordinarily be made of some highly iefractor material,- preferably carborundum, while the rear section 3 will be made of some relatively inexpensive and less refractory material, such as fire clay. For some purposes it maybe satisfactory to make both sections of fire clay or of some other lmaterial having similar characteristics. A In a' typical furnace, ksuch for example, as that shown in Fig. 4, the furnace wall is made hollow; or, in other words, is provided with an air chamber 14, Fig. 4, immediately behind the furnace lining 15. 'Air under pressure is forced into the chamber '14 while the furnace is being operated, and this air flows through the holes 12 and 10 to the face of the lining. This materially reduces the temperature of the lining. The lining is further cooled by the air which flows through the hole 13 into the air space 8, circulates through this space, and then mingles with the air that iows throu h the holes 10. While some circulation in t e air s ace 8 undoubtedly would be produced if t e hole 13 were omitted, I prefer to provide some means for establishing a more vigorous circulation of v air through this space than would be reduced simply by edd currents created y air flowing throng the holes 10.

'It will now be evident that thisv invention rovides a brick for furnace linings which 1s plarticularly well adapted to withstand hig temperatures, while at the same time being so constructed that it can be manufactured very economically. The fact that the front or facing section is relativelyv thin facilitates the conduction of heat through the lining to the air space, from which it is swept away by the continuous circulation of air. Excessive heating of the furnace linin thus is prevented.

, ile I have herein shown and described the best embodiment of my invention that I have so far devised, it is contemplated that the invention may be embodied inA many other forms without departing `from the spirit or scope thereof. For example, variois arrangements of air passages may be use Having thus described my invention, what I desire to claim as new is:

1. A fire brick comprising front'and rear sections of refractory material with their marginal portions secured together and their central'portions separated from each other by an air space of substantial area, said rear section having kone or more air passages, extending therethrough and opening into said air space.

2. A fire brick comprising front and rear sections of refractory material with their marginal portions secured together and their central portions separated from each other by an air space of substantial area, said sections each having a plurality of air conduct' holes formed therethrough substantially 1n alinement with each other, and the rear section having an additional hole opening into said air space and ofset with reference to the holes 1n said .front section.

3. A fire brick comprising front and rear sections of refractory material secured together with an air s lace separating said sections throughout a ldrge part of their areas, and each of said sections havin an air hole formed therethrough and openlnginto Said air space.Y

4. A tire brickcomprising front and rear sections of refractory material secured together with an air space separating said sections throughout a large part of their areas, and each of said sections having air holes 'formed therethrough and o ening into said air space, certain of the ho es through said rear section being in alinement with the holesthrou'gh the front section, and an additional hole through said rear section communicating with said air space and out of alinement with the holes in the front section.

5. A fire brick comprising front and rear sections of refractor material having marginal portions inter ocked with each other and their central portions separated from each other by 'an air spacel of substantial area, the material of the front section being more refractory than that of the rear section, and said Vrear section having one or more air passages lextending therethrough and openin into said air space.

6. A firegbrick comprising -front and rear sections 'of non-metallic refractory material interlockingly engaged at marginal portions but shaped to provide an air s ace of substantial area immediately behin the central portion of saidfront section, one of said Sectionsv having anv air passage formed therethrough and opening/into said air space.

7. A fire brick comprising front and rear sections of non-metallic refractory material permanently attached -to each other and shaped to provide an air chamber between them, said front section being of more refractory material than the rear section, and said brick havin one or more air passages opening into sai air chamber.

8. A ire brick comprising front and rear in an air space of substantial area imme`.

diately behind the central portion `of said front section, a plurality of air holes extending from said space ythrough said front section, and an air hole extending through said rear section and opening into said space, said front section being made of more refractory material than the rear section. I

9. A fire brickcomprising front and rear sections ofnonmetalhc refractory material marginally. interlocked with each other and shaped to provide an air chamber between them, said front section being of more refractory material than the'rear section and said brick having one or more air passages opening into said air chamber.

,10. A re brick comprising front and rear sections of nonmetallic refractory material having marginal portions interlockingly engaged and s aped to provide an air chamber therebetween, said brick having one or more air passages opening into said air chamber.

11. A fire brick comprising front and rear sections of nonmetallic refractory material permanently attached to each other and shaped to provide an air chamber therebetween, and said brick being constructed to `use a circulation of air through said chamr. 12. A fire brick comprising front and, rear Sections of refractory material permanently fire brick having front and rear sections of attached to each other and shaped to prononmetallic refractory material interlocked -vide an air chamber' therebetweenand said with each other and shaped to provide an air l0 brick havingl passages therethrough archamber between the sections of brick, said 5 ranged to circulate air through said chamber. bricks each having one or more air passages 13. A furnace Wall formed of front and opening into said air chamber. rear sections, said front section comprising OSCAR NYGAARD. 

